Emerson Keystone Figure 637, Руководство по обслуживанию

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Emerson Radio
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A D D E N D U M S E R V I C E N O T E
T E L E V I S I O N R E C E I V E R S
MODELS 614,, 637, 644, and 647
CHASSIS MODELS 1201 IOC and 120113C
I. GENERAL
The models listed have been revised both mechanically and electrically. The major mechanical change is the conversion
to two dual-controls in place of the original arrangement of four dual-controls. Such models and chassis are identified by
the subscript C or BC, as for example Model 644C. The major electrical change is the use of a multivibrator circuit in place
of a blocking oscillator, in the vertical deflection circuits. This revision applies to both B and C chassis.
The change in the arrangement of operating controls is illustrated in figure 1. The Vertical Hold control* and Brightness
and Horizontal Hold controls, are located at the rear of the chassis, as shown in figure 2. Mechanical centering is provided by
use of a movable focus coil controlled by a lever. The centering lever may be tilted both up and down, and side to side.
HORIZONTAL HOLD CONTROL:
STOPS HORIZONTAL MOTION
OF PICTURE.
REAR CONTROLS
3RIGHTNESS CONTROL:-
ADJUSTS PICTURE
\A V ER A G E BRIGHTNESS.
\
Fig,
2— Rear Adjustment Controls
HOR. HOR. HOR VERT. VERT. FO CUS
v e r t
\
S IZ E
LIN.
DRIVE
LIN.
S IZ E HOLD
V
0
0
o
o o
O
O ©
2. VERTICAL MULTIVIBRATOR - "
Chassis code marking Triangle 6, stamped at the rear of chassis 120110B or 120113B, includes the change of the vertical
sweep generator to the multivibrator type, with an auto-transformer in the output circuit. This revision is indicated in the
schematic diagram, figure 3. All previous modifications, listed in the present service manual, are included.
3. M EC H A N IC A L CENTERING
Use of mechanical centering controlled by the "wobble” plate and focus coil lever (picture centering lever) is indicated by
code marking Triangle 7. The Horizontal Centering control, R-103, part no. 390107, is replaced by a 10 ohm, ^2 wa*t
resistor.
•
4. BC and C TYPE CHASSIS
Mechanical revision of chassis 120110B and 120113B, to provide for the control arrangement previously outlined, re­
sulted in chassis 120110C and 120113C. Note that the code markings applicable to the C-type chassis differ from those assigned
to the B-type chassis. Chassis marked BC are identical in control arrangement with C chassis but make use of extension brackets
for several controls.
5. TUNER REVISIONS
The "Standard” turret tuner, part no. 470603, originally used in the models listed, has been modified as to shaft length,
and becomes part no. 470607. The C-type chassis may use an alternate tuner, part no. 470605, produced by "Automatic.”
Such chassis are identified by code marking Triangle O. N o circuit modifications are entailed; however, the arrangement and
location of alignment trimmers and oscillator slugs differs, as shown in figure 4.
Scanned by mbear2k - Jan 20121/17